SCIENCE & NATURE
The giant variety of this, Tridacna gigas, is the largest living bivalve mollusk & can grow to 4 feet across & 500 pounds
A clam
Unlike Hägar's, the first complete Viking helmet ever found lacks these, largely an invention of a 19th century Wagner opera designer
Horns
Similar to a certain staircase, this type of tunnel in Norway coils its way up the inside of a hill for over a mile
A spiral
On Oct. 22, 1962 JFK announced a naval blockade of this country due to Soviet missiles being discovered there
Cuba
A lack of genetic diversity in this crop in 1840s Ireland was a major cause of disaster for the population
A potato
Aside from the Sun & the Moon, this is the brightest natural object in the night sky
Venus
In 2000 the U.S. & Iceland each issued a coin to honor the 1000 A.D. discovery of the New World by this man
Leif Erikson
South Africa's over 50-mile-long Orange-Fish Tunnel gets its name from 2 of these that it connects
Rivers
After a historic 1983 mission, this astronaut turned down flowers as her male counterparts weren't given any
Sally Ride
The USSR's 1930s Great Purge included the notorious "show" type of these, with defendants forced to confess
Trials
After sulfur is removed, this has no odor; mercaptan is added to it so that leaks can be detected
Natural Gas
Norse games of myth included hnutukast, taking these from the carcass after a meal & throwing them at each other with intent to injure
Bones
Dixia Cheng, a sprawling network of tunnels in Beijing, is aka the "Underground" this other landmark
The Great Wall
Victoria Woodhull was the first woman to run for pres. in 1872, but couldn't have taken office because she wasn't yet this age
35
1950-51 in the Alps was the "Winter of Terror" as these disasters destroyed buildings & killed more than 200 people
Avalanches
Studying flares & the corona, in 2019 U.K. astronomers determined that this field is 10 times stronger than previously thought
The Sun's magnetic field
This name given to the northeast coast of North America by the Norsemen reflected the plants they found growing there
Vinland
Honoring a Santa Monica newspaper publisher, the McClure Tunnel takes you north on this scenic highway aka Highway 1
The Pacific Coast Highway
This president was said to regret his decision "not to hang John C. Calhoun" as a traitor
Andrew Jackson
The Vatican had second thoughts about its treatment of heretic Giordano Bruno--400 years after he was executed this way
Burned at the stake
Butterflies emerge as adults not from a cocoon but from one of these structures whose name is from the Greek for "gold"
Chrysalis
The longest known inscriptions in this Viking alphabet is on the Rökstenen
the Runic alphabet
The world's highest vehicular tunnel is on I-70, 60 miles west of this state capital
Denver
This 1620 document mentions "our dread sovereign Lord King James", "a voyage to plant the first colony" & "Cape Cod"
The Mayflower Compact
A secret Sicilian group fighting foreign invaders may be the origin of this notorious criminal group
the Mafia